The pardons include 86 foreign nationals from 25 countries, and will take place "in the coming days," Castro said in a closing address to the National Assembly Friday.

However US contractor Alan Gross, jailed in Cuba for espionage, will not be among those to be released, top Foreign Ministry official Josefina Vidal told AFP.

Cuba's planned transition to a market economy

Gross - a State Department contractor arrested in December 2009 for delivering laptops and communications gear to Cuba's small Jewish community - "will not be on the list" of foreigners to be pardoned, the official said.

Castro said factors that played into the pardon decision included requests from the Catholic Church and various Protestant churches, and the visit of Pope Benedict XVI in 2012.

The pardon is the largest ever under the communist regime, much larger that the 299 prisoners released ahead of the visit of Pope John Paul II in January 1998.

Cubans were intensely and emotionally keen to hear about migration reform, which Castro -- the ex-defense chief who took over from his brother, revolutionary icon Fidel Castro, in July 2006 -- has promised but not yet delivered.

Many people "consider a new migratory policy an urgent issue, forgetting the exceptional circumstances that Cuba is going through," he added.

He referred to the US trade embargo on the island and Washington's alleged "subversive" policy, "always on the lookout for any opportunity to reach its known purposes."

Neither the communist government nor the state-run media have given details of the migration reforms being considered.

Local experts believe Castro intends to end the requirement of exit visas (for Cubans on the island), entrance visas (for Cubans living overseas who return home) and the legal status of "permanent emigrant."

Cubans usually can only leave the country when they have received a letter of invitation from overseas. Then, they have to file a request for an exit visa, just at the start of a maze-like bureaucratic process that costs about $500.

They also need entry visas from the countries to which they travel.

The price is near unaffordable in Cuba, where doctors and street cleaners alike make about 20 dollars a month.

The Roman Catholic Church and regime-friendly personalities have joined a chorus of Cubans calling for an end to the rules, including one that penalizes "permanent emigrants" from the only one-party Communist regime in the Americas.

Those who are deemed to have left illegally (permanent emigrants) in essence are classed as defectors, their homes and assets seized.

Castro did not give details about who would be released, but did say that among the foreigners were 13 women. The release of the foreigners would depend on "whether the governments of their countries of origin accept their repatriation," Castro said.

However the highest-profile prisoner, US citizen Gross, will not be leaving.

Gross, 62, was found guilty in March of "acts against the independence or territorial integrity" of Cuba and sentenced to 15 years in prison. He has already spent two years behind bars in Cuba.

Washington renewed its calls on December 2 for Gross's immediate release.

Earlier this month, a group of 19 US senators sent a letter to the head of the Cuban interests section in Washington, Jorge Bolano, asking the Cuban government to consider the health and economic conditions of the Goss family.

"Mr. Gross has lost 100 pounds and suffers from numerous medical conditions," they wrote. "Mr. Gross's daughter and mother are both fighting cancer, and his wife is struggling to make ends meet."